Electric heating apparatus



June 28, 1955 F. GALLAY ELECTRIC HEATING APPARATUS Filed Jan. 6, 1953HTTOP/VEQ United States Patent ELECTRIC HEATING APPARATUS FrancisGallay, Collonge-Bellerive, Switzerland, assignor to Intertherm A.-G.,Fahrik fur elektrische Apparate (Intertherm S. A., Fabrique dappareilselectriques), Zurich, Switzerland, a corporation of SwitzerlandApplication January 6, 1953, Serial No. 329,816 Claims priority,application Switzerland January 15, 1952 6 Claims. (Cl. 219-39) Thepresent invention concerns an electric heating apparatus destined to beused for the heating of rooms.

in the apparatus used up to now the elements of the heating body areusually formed by a helically coiled resistance wire, and, in mostcases, are arranged in a plane or parallel to a surface of revolutionsuch as a cylinder.

It has been noticed that heating bodies of this kind are often damagedand put out of action owing to the formation of danger zones in whichcertain points are overheated, especially in cases where a fan destinedto send a stream of air through the said elements accidentally stops.This disadvantage is mainly due to the fact that when the elements arearranged, inadequate use is made of the space available for the heatingbody, so that the elements do not heat the air in a homogeneous fashion.

The object of the present invention is to remedy these disadvantages,and in view of this, the heating apparatus according to the invention isfitted with a heating body comprising at least one electric wireresistance composed of heating elements having a generally rectilinearshape, the apparatus comprising, in addition, a chimney the ends ofwhich are fitted with fastening means for the said elements and whichforms a support for the same, the said elements being arranged insidethe said chimney and extending from one end of the chimney to the otherin directions which are oblique in relation to the axis of the chimney,the projections of the said elements on a plane perpendicular to theaxis of the chimney forming at least one star-shaped polygon.

The accompanying drawings show, by way of example, an embodiment of theheating apparatus according to the invention.

Fig. 1 shows a sectional elevation of this example through 11 in Fig. 2.

Fig. 2 shows a cross-section through 22 in Fig. l; and

Fig. 3 is an enlarged view of a detail.

The heating apparatus shown is fitted with a heating body comprising asupport 1 for the heating elements 2 of an electric wire resistance, forinstance made with a nickel-chrome wire, helically wound so as to form acylindrical coil. The support 1 is formed by a metallic drum which isopen at both ends and which is destined to form a chimney through whichflows a current of air, as will be fully described further on.

Each of the edges 3 and 4 of the drum is slit from place to place for aheight of from 2 to 3 crns. so as to allow the sheet metal of the drumto be bent inwards to form triangular lugs 5. These lugs 5 are eachprovided with a slot 6 in which is inserted an insulator 7 through whichpasses a cotter pin 8 to which the heating elements 2 are hooked (Fig.3). Other means for fastening the elements 2 might be provided insteadof the cotter pins. In particular one could use hooks fixed to theinsulators in an appropriate manner. The height of the slits in theedges of the drum and the width of the lugs are such that the plane ofeach lug is approximately perpendicular to the bisector of the angleformed by the two elements hooked to the said lug.

The electric resistance coil is hooked to the insulators 7 and passesfrom an insulator of the upper edge 3 to an insulator of the lower edge4 which is situated about further along that edge, to return to the nextinsulator on the upper edge. The rectilinear elements 2 are thusarranged inside the chimney, and extend from one end to the other of thesaid chimney in directions which are oblique in relation to the axis A-Aof the chimney. As will be seen in Fig. 2, the projections of theelements 2 on a plane perpendicular to the axis AA, and the trace ofwhich coincides with the line 22 in Fig. 1, form a star-shaped polygon.

Instead of being provided with bent lugs, the edges 3 and 4 of the drum1 could be provided with slots into which the means to which the heatingelements are hooked would be directly inserted.

The heating body described above is mounted in a casing 9, the generalshape of which is ovoid and which is supported on a base 10 forming thecasing of a fan motor 11. The casing 9 is in two parts which fit intoone another at their greatest diameter and which are assembled by meansof spring catches, placed at intervals along the circumference andengaging in slots of the inner and outer parts, as shown in Fig. l. Thecatches can be brazed or fixed in any other appropriate manner to thelower half of the casing 9. The air drawn in by the fan 11 enters byopenings 13 in the lower half of the casing 9, fiows through the chimneyformed by the supporting drum 1 of the heating body and escapes in aheated state through the openings 14. N0 openings are provided in thecentral portion of the casing 9, comprising about /3 of its height. Adeflector 15 is fixed centrally under the bottom 16 of the upper half ofthe easing and comprises a cylindrical tube 17 extending to within ashort distance of the centre of the fan, and surmounted by a truncatedcone the largest diameter of which is adjacent to the bottom 16. Thisdeflector is destined to canalize the flow of air as shown by the arrowsin Fig. 1 and to prevent the bottom 16 and the carrying handle 16 frombecoming unduly hot.

The metallic drum forming the aforementioned chimney constitutes theinner wall of a space 19 formed be tween this chimney and the casing 9.The casing 9 is provided with openings 20 at the upper part of the space19, so that the suction created by the fan at the lower end of the space19 causes cold air to flow downwards through this space in the directionindicated by the arrows and to cool the wall of the casing 9.

The principal advantage of the heating apparatus described above, isthat, in case of an accidental stoppage of the fan, dangerous Zones withoverheated points do not appear in the heating body. It is to be notedthat the heating elements are arranged to form an annular mesh whichenables the air flowing through the drum to be heated in a more evenmanner than if the heating elements were arranged in a cylindricalsurface according to the usual practice in apparatus of this type.

The apparatus described above has the additional advantage of being verysturdy and is very simple and cheap to build. In the example of theheating body described above, the heating elements of the singleresistance consist of a single continuous wire, so that only twoconnexion leads are required. It would also be possible to use two ormore heating resistances dovetailed into one another and staggered, andarranged to function singly, in parallel or in series, according to themode of heating desired. In that case the projections on a planeperpendicular to the axis of the heating body of the heating elements ofthe various resistances would form two or more star-shaped polygons.

What I claim is: 1. An electric heater comprising a sleeve forming anair flue, at least one electrical resistance wire composed of generallyrectilinear heating elements, and fastening means at both ends of saidsleeve for supporting said heating elements, all of said elementsextending obliquely inside the sleeve from one end thereof to the otherand each element crossing a plane through the axis of the sleeve, theprojection of said elements on a plane perpendicular to the axis of thesleeve forming at least one starshaped polygon.

2. An electric heater as defined in claim 1, wherein said fasteningmeans comprises a plurality of substantially evenly spaced insulatedfasteners at each end of the sleeve, and the electrical resistance wireis so arranged on said fasteners that one end of each heating element isattached to a fastener at one end of the sleeve and the other end of theheating element is attached to a fastener at the other end of the sleevewhich is staggered a predetermined circumferential distance from thefastener at the one end.

3. An electric heater as defined in claim 2, wherein said predeterminedcircumferential distance is determined by an angle of 90.

4. An electric heater comprising, in combination, a generally ovoidouter casing including a base; a fan mounted on said base; a metallicsleeve forming an air flue mounted in said casing above said fan; thesleeve and the casing forming a space therebetween and the casing beingprovided with openings at the upper end of the space, rotation of thefan causing air entering from the outside through the openings into saidspace to fiow in a stream from top to bottom of the space to cool thesleeve and easing walls; at least one electrical resistance wire acomposed of generally rectilinear heating elements; and fastening meansat both ends of said sleeve for supporting said heating elements, all ofsaid heating elements extending obliquely inside said sleeve from oneend thereof to the other and each element crossing a plane through theaxis of the sleeve, the projection of said elements on a planeperpendicular to the axis of the sleeve forming at least one star-shapedpolygon.

5. In an electric heater comprising at least one elec trical resistancewire composed of generally rectilinear heating elements supported by asurrounding sleeve: an arrangement of the heating elements wherein eachelement crosses obliquely a plane through the axis of the sleeve and theprojection of said elements on a plane pe.- pendicular to the axis ofthe sleeve forms at least one star-shaped polygon.

6. An arrangement of heating elements as defined in claim 5, wherein theelectrical resistance wire is so arranged that one end of each heatingelement is attached at one end of the sleeve and the other end of theheating element is attached at the other end of the sleeve apredetermined circumferential distance staggered from the attachment atthe one end.

References Cited in the file of this patent UNlTED STATES PATENTSConforti Oct. 11,

